/**
 * storgae封装
 */
const STORAGE_KEY = 'mall';

export default {

    //
    setItem(key,value,module_name){
        if(module_name){
            let val = this.getItem(module_name);
            val[key] = value;
            this.setItem(module_name,val);
        }else{
            let val = this.getStorage();
            val[key] = value;
            window.sessionStorage.setItem(STORAGE_KEY,JSON.stringify(val));
        }
    },
    // 获取某个模块下的属性
    getItem(key,module_name){
        if(module_name){
            let val = this.getItem(module_name);
            if(val){
                return val[key];
            }
        }
       return this.getStorage()[key];
    },
    //
    getStorage(){
        return JSON.parse(window.sessionStorage.getItem(STORAGE_KEY)||'{}') ;
    },
    //
    clear(key,module_name){
        let val = this.getStorage();
        if(module_name){
            delete val[module_name][key];
        }else{
            delete val[key];
        }
        window.sessionStorage.setItem(STORAGE_KEY,JSON.stringify(val));
    }
}